The invention relates to an automotive machine for producing carriageways. Such machines are needed for the conditioning of material, namely the stabilization of insufficiently stable soils, the pulverization of hard asphalt pavements to the recycling of bound or unbound carriageway surfaces.
The known construction machines mostly show a working drum that revolves in a working chamber and is generally arranged in a height-adjustable manner for adjustment to the required milling depth and the surface to be worked. An adjustment of the slope can be effected by means of the running gear.
Adapted to the particular applications, the particular processes, such as removing and crushing the milled carriageway material, adding binding agents, mixing and spreading added materials, take place in this working chamber that is confined by a cover. A detailed explanation of the tasks to be solved by such machines and of the problems occurring can be inferred from WO 96/24725, which is referred to herewith in terms of content.
In the construction machine described therein, the cover is firmly attached to the machine chassis. The combustion engine for the drive power is mounted on a pivoting bracket, in the pivoting arms of which the milling drum is also mounted on both sides. The device, consisting of pivoting bracket with combustion engine and pivoting arms with milling drum, is mounted to pivot in the machine chassis. This arrangement influences any energy, substance and signal flow from and to the combustion engine in an unfavourable manner.
A further prior art is known from DE 3921875. The machine described therein shows a milling drum mounted between two pivoting arms that is surrounded by a height-adjustable cover. The combustion engine for the drive shows a hydraulic pump for the milling drive and a drive pump, both of which are coupled to a combustion engine arranged in front of the front axle of the running gear in a longitudinal direction. Here, the combustion engine is arranged in a fixed manner at the machine chassis but in an unfavourable manner in front of the operator's platform, which impedes the view, and in particular in front of the front axle, which adversely affects the position of the machine's centre of gravity. Furthermore, the hydraulic drive of the milling drum has a poor efficiency.
U.S. Pat. No. 5,354,147 describes a prior art with the features of the pre-characterizing clause. Of disadvantage here are the considerable design effort and the unfavourable weight distribution of the machine weight due to the combustion engine installed in front of the front axle. The arrangement of the engine in a longitudinal direction requires an additional gearbox, which makes the machine more expensive and more susceptible and reduces the efficiency of the milling drum drive.
Starting from a prior art in accordance with U.S. Pat. No. 5,354,147, the purpose of the invention consists in creating an automotive machine for producing carriageways that facilitates a mechanical direct drive of the working drum at a generally more stiff drive system and improved position of the centre of gravity.
The invention provides in a favourable manner that the combustion engine is arranged in a fixed manner at the machine chassis between the pivoting arms and that at least one mechanical power transmission device, together with the working drum mounted in the pivoting arms, can be pivoted about the output shaft of the combustion engine.
The advantage of the mechanical drive is that, due to the direct coupling of the combustion engine and the milling drum, an increased torque can be realized and drive losses are reduced, since no mechanical energy needs to be converted into hydraulic energy first and then back again into mechanical energy. At the same time, the drive system is stiffer when compared to a hydraulic drive system.
Arranging the output shaft of the combustion engine parallel to the shaft of the working drum allows the working drum with the power transmission device to be pivoted about the axis of rotation of the output shaft in a favourable manner without requiring additional mechanical elements. In doing so, the combustion engine can be installed transversely to the direction of travel in a favourable manner. Because the combustion engine is attached to the machine chassis in a fixed manner, suction and exhaust pipes as well as supply lines (e.g. for fuel, cooling liquid, engine electrics, hydraulics, etc.) need not be designed in a flexible manner.
Arranging the combustion engine between the support of the pivoting arms in the machine chassis has the advantage of a space-saving design and enables the power transmission device to be coupled directly to the output shaft at the combustion engine.
Between the output shaft and the power transmission device, a clutch can also be arranged in combination with a pump transfer gearbox.
In one preferred embodiment, it is intended that the output shaft of the combustion engine is arranged coaxially with the crankshaft axle of the combustion engine.
An operator's platform is preferably arranged in front of the combustion engine in the direction of travel. In a particularly favourable design, the operator's platform can be arranged in front of the front wheels. This arrangement has the additional advantage that the operator's platform can be movable in transverse direction.
The running gear can show front and rear wheels, whereby the front or the rear or all wheels are driven. The operator's platform can preferably be arranged in front of the axles of the front wheels.
The running gear preferably shows front steerable and/or rear steerable wheels.
The arrangement of the combustion engine between the drive axles is favourable for the weight distribution and enables the contact pressure on the working drum to be increased.
It is understood that the running gear can also show other drive means, e.g. track chains, in lieu of wheels. The preferred embodiment is provided with individual wheels that can, however, also be jointly controlled.
At least one of the pivoting arms, which are mounted to pivot in the machine chassis, receives the power transmission device between the combustion engine and the working drum.
In principle, however, there is also the possibility of guiding the output shaft through both sides of the transversely installed combustion engine and to provide a power transmission device in both pivoting arms. If a mechanical power transmission device is intended on one side only, the pivoting arm on the other side can be designed in a flat manner so that milling close to the edge is possible on this so-called zero side, i.e. the distance of the front edge of the working drum from an obstacle can be minimized on this zero side.
The working drum is coupled to a lifting device showing a link mechanism and attached to the machine chassis, by means of which the milling depth can be set.
The working drum can be coupled to one lifting device each on both front ends, whereby the movements of both lifting devices are synchronized.
In detail, the lifting device can show two pull rods running parallel to each other that are flexibly mounted at the pivoting arms on both sides at the working drum.
The lifting device can show at least one two-armed lever, one lever arm of which is connected to the free end of the pull rods and the other lever arm of which is flexibly coupled to a piston cylinder unit that is attached to the machine chassis.
The link mechanism enables the transmission of high forces due to the leverage ratio and enables a large stroke at a low design height.
In case of an arrangement of two-armed levers on both sides, it is intended that both levers are connected to each other in a non-rotatable manner by a coupling device that runs parallel to the shaft of the working drum and is mounted in the machine chassis, e.g. a connecting pipe.
In the following, embodiments of the invention are explained in more detail with reference to the drawings. The following is shown: